<script id="draw-shader-vs" type="x-shader/x-vertex">
precision mediump float;

attribute vec3 inPos;
attribute vec3 inNV;
attribute vec3 inCol;

varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;

uniform mat4 u_projectionMat44;
uniform mat4 u_modelViewMat44;

void main()
{
    vertNV      = mat3( u_modelViewMat44 ) * normalize( inNV );
    vertCol     = inCol;
    vec4 pos    = u_modelViewMat44 * vec4( inPos, 1.0 );
    vertPos     = pos.xyz / pos.w;
    gl_Position = u_projectionMat44 * pos;
}
</script>

<script id="draw-shader-fs" type="x-shader/x-fragment">
precision mediump float;

varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;

uniform float u_shininess;

void main()
{
    vec3 color = vertCol;
    vec3  normalV  = normalize( vertNV );
    vec3  eyeV     = normalize( -vertPos );
    vec3  halfV    = normalize( eyeV + normalV );
    float NdotH    = max( 0.0, dot( normalV, halfV ) );
    float shineFac = ( u_shininess + 2.0 ) * pow( NdotH, u_shininess ) / ( 2.0 * 3.14159265 );
    gl_FragColor   = vec4( color.rgb * (0.2 + NdotH), 1.0 );
} 
</script>

<script id="post-shader-vs" type="x-shader/x-vertex">
precision mediump float;

attribute vec2 inPos;

varying   vec2 pos;

void main()
{
    pos = inPos;
    gl_Position = vec4( inPos, 0.0, 1.0 );
}
</script>

<script id="blur-shader-fs" type="x-shader/x-fragment">
precision mediump float;

varying vec2 pos;

uniform sampler2D u_texture;
uniform vec2      u_textureSize;
uniform float     u_sigma;
uniform float     u_radius;
uniform vec2      u_dir;

float CalcGauss( float x, float sigma )
{
    if ( sigma <= 0.0 )
        return 0.0;
  return exp( -(x*x) / (2.0 * sigma) ) / (2.0 * 3.14157 * sigma);
}

void main()
{
    vec2 texC     = pos.st * 0.5 + 0.5;
    vec4 texCol   = texture2D( u_texture, texC );
    vec4 gaussCol = vec4( texCol.rgb, 1.0 );
    vec2 step     = u_dir / u_textureSize;
    for ( int i = 1; i <= 32; ++ i )
    {
        float weight = CalcGauss( float(i) / 32.0, u_sigma * 0.5 );
        if ( weight < 1.0/255.0 )
            break;
        texCol    = texture2D( u_texture, texC + u_radius * step * float(i) );
        gaussCol += vec4( texCol.rgb * weight, weight );
        texCol    = texture2D( u_texture, texC - u_radius * step * float(i) );
        gaussCol += vec4( texCol.rgb * weight, weight );
    }
    gaussCol.rgb = clamp( gaussCol.rgb / gaussCol.w, 0.0, 1.0 );
    gl_FragColor = vec4( gaussCol.rgb, 1.0 );
}
</script>

<style>
html,body { margin: 0; overflow: hidden; }
#gui { position : absolute; top : 0; left : 0; font-size : large; }
#ref-link { position : absolute; bottom : 0; left : 0; font-size : large; }  
</style>

<body>
  
<div>
<form id="gui" name="inputs">
<table>
<tr> <td> <font color= #CCF>radius</font> </td> 
        <td> <input type="range" id="radius" min="1" max="1000" value="1000" onchange="changeEventHandler(event);"/></td> </tr>
<tr> <td> <font color= #CCF>blur</font> </td> 
        <td> <input type="range" id="sigma" min="1" max="100" value="5" onchange="changeEventHandler(event);"/></td> </tr>
</table>
</form>
</div>

<div id="ref-link">
<a href="https://stackoverflow.com/questions/50882953/glsl-gaussian-blur-artifact-issue/50885727#50885727"> 
<font color= #CCF>GLSL - Gaussian Blur Artifact Issue</font>
</a>
<br/>
<a href="https://stackoverflow.com/questions/8166384/how-to-get-a-glow-shader-effect-in-opengl-es-2-0/45043547#45043547"> 
<font color= #CCF>How to get a "Glow" shader effect in OpenGL ES 2.0?</font> 
</a>
<br/>
<a href="https://stackoverflow.com/questions/11282394/what-kind-of-blurs-can-be-implemented-in-pixel-shaders/45878733#45878733">
<font color= #CCF>What kind of blurs can be implemented in pixel shaders?</font>
</a>
<br/>
<a href="https://stackoverflow.com/questions/44779142/opengl-es-2-0-gaussian-blur-on-triangle/45238087#45238087">
<font color= #CCF>OpenGL es 2.0 Gaussian blur on triangle</font>
</a>
</div>

<canvas id="canvas" style="border: none;"></canvas>

<script type="text/javascript">

var readInput = true;
function changeEventHandler(event){
readInput = true;
}

(function loadscene() {

var resize, gl, progDraw, progBlur, vp_size, blurFB;
var canvas;
var camera;
var bufCube = {};
var bufQuad = {};
var shininess = 10.0;
var glow = 10.0;
var sigma = 0.8;
var radius = 1.0;

function render(deltaMS){

    if ( readInput ) {
        //readInput = false;
        var sliderScale = 100;
        sigma     = document.getElementById( "sigma" ).value / sliderScale;
        radius    = document.getElementById( "radius" ).value / sliderScale;
    }

    vp_size = [canvas.width, canvas.height];
    camera.Update( vp_size );
        
    gl.enable( gl.DEPTH_TEST );
    gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
    gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );

    // set up framebuffer
    gl.bindFramebuffer( gl.FRAMEBUFFER, blurFB[0] );
    gl.viewport( 0, 0, blurFB[0].width, blurFB[0].height );
    gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );

    // setup view projection and model
    var prjMat = camera.Perspective();
    var viewMat = camera.Orbit();
    var modelMat = IdentM44();
    modelMat = camera.AutoModelMatrix();
    
    // set up draw shader
    ShProg.Use( progDraw );
    ShProg.SetM44( progDraw, "u_projectionMat44", prjMat );
    ShProg.SetM44( progDraw, "u_modelViewMat44", Multiply(viewMat, modelMat) );
    ShProg.SetF1( progDraw, "u_shininess", shininess );
    
    // draw scene
    VertexBuffer.Draw( bufCube );

    // set blur-X framebuffer and bind frambuffer texture
    gl.bindFramebuffer( gl.FRAMEBUFFER, blurFB[1] );
    gl.viewport( 0, 0, blurFB[1].width, blurFB[1].height );
    gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
    var texUnit = 1;
    gl.activeTexture( gl.TEXTURE0 + texUnit );
    gl.bindTexture( gl.TEXTURE_2D, blurFB[0].color0_texture );

    // set up blur-X shader
    ShProg.Use( progBlur );
    ShProg.SetI1( progBlur, "u_texture", texUnit )
    ShProg.SetF2( progBlur, "u_textureSize", vp_size );
    ShProg.SetF1( progBlur, "u_sigma", sigma )
    ShProg.SetF1( progBlur, "u_radius", radius )
    ShProg.SetF2( progBlur, "u_dir", [1.0, 0.0] )

    // draw full screen space
    gl.enableVertexAttribArray( progBlur.inPos );
    gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos );
    gl.vertexAttribPointer( progBlur.inPos, 2, gl.FLOAT, false, 0, 0 ); 
    gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx );
    gl.drawElements( gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0 );
    gl.disableVertexAttribArray( progBlur.inPos );

    // reset framebuffer and bind frambuffer texture
    gl.bindFramebuffer( gl.FRAMEBUFFER, null );
    gl.viewport( 0, 0, vp_size[0], vp_size[1] );
    gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
    texUnit = 2;
    gl.activeTexture( gl.TEXTURE0 + texUnit );
    gl.bindTexture( gl.TEXTURE_2D, blurFB[1].color0_texture );

    // set up pst process shader
    ShProg.SetI1( progBlur, "u_texture", texUnit )
    ShProg.SetF1( progBlur, "u_radius", radius )
    ShProg.SetF2( progBlur, "u_dir", [0.0, 1.0] )

    // draw full screen space
    gl.enableVertexAttribArray( progBlur.inPos );
    gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos );
    gl.vertexAttribPointer( progBlur.inPos, 2, gl.FLOAT, false, 0, 0 ); 
    gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx );
    gl.drawElements( gl.TRIANGLES, 6, gl.UNSIGNED_SHORT, 0 );
    gl.disableVertexAttribArray( progBlur.inPos );

    requestAnimationFrame(render);
}

function initScene() {

    canvas = document.getElementById( "canvas");
    gl = canvas.getContext( "experimental-webgl" );
    if ( !gl )
        return null;

    progDraw = ShProg.Create( 
    [ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
        { source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
    ] );
    if ( !progDraw.progObj )
        return null;
    progDraw.inPos = gl.getAttribLocation( progDraw.progObj, "inPos" );
    progDraw.inNV  = gl.getAttribLocation( progDraw.progObj, "inNV" );
    progDraw.inCol = gl.getAttribLocation( progDraw.progObj, "inCol" );

    progBlur = ShProg.Create( 
    [ { source : "post-shader-vs", stage : gl.VERTEX_SHADER },
        { source : "blur-shader-fs", stage : gl.FRAGMENT_SHADER }
    ] );
    progBlur.inPos = gl.getAttribLocation( progBlur.progObj, "inPos" );
    if ( !progBlur.progObj )
        return;    
    
    // create cube
    var cubePos = [
    -1.0, -1.0,  1.0,  1.0, -1.0,  1.0,  1.0,  1.0,  1.0, -1.0,  1.0,  1.0,
    -1.0, -1.0, -1.0,  1.0, -1.0, -1.0,  1.0,  1.0, -1.0, -1.0,  1.0, -1.0 ];
    var cubeCol = [ 1.0, 0.0, 0.0, 1.0, 0.5, 0.0, 1.0, 0.0, 1.0, 1.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 1.0 ];
    var cubeHlpInx = [ 0, 1, 2, 3, 1, 5, 6, 2, 5, 4, 7, 6, 4, 0, 3, 7, 3, 2, 6, 7, 1, 0, 4, 5 ];  
    var cubePosData = [];
    for ( var i = 0; i < cubeHlpInx.length; ++ i ) {
    cubePosData.push( cubePos[cubeHlpInx[i]*3], cubePos[cubeHlpInx[i]*3+1], cubePos[cubeHlpInx[i]*3+2] );
    }
    var cubeNVData = [];
    for ( var i1 = 0; i1 < cubeHlpInx.length; i1 += 4 ) {
    var nv = [0, 0, 0];
    for ( i2 = 0; i2 < 4; ++ i2 ) {
        var i = i1 + i2;
        nv[0] += cubePosData[i*3]; nv[1] += cubePosData[i*3+1]; nv[2] += cubePosData[i*3+2];
    }
    for ( i2 = 0; i2 < 4; ++ i2 )
    cubeNVData.push( nv[0], nv[1], nv[2] );
    }
    var cubeColData = [];
    for ( var is = 0; is < 6; ++ is ) {
    for ( var ip = 0; ip < 4; ++ ip ) {
        cubeColData.push( cubeCol[is*3], cubeCol[is*3+1], cubeCol[is*3+2] ); 
    }
    }
    var cubeInxData = [];
    for ( var i = 0; i < cubeHlpInx.length; i += 4 ) {
    cubeInxData.push( i, i+1, i+2, i, i+2, i+3 );   
    }
    bufCube = VertexBuffer.Create(
    [ { data : cubePosData, attrSize : 3, attrLoc : progDraw.inPos },
    { data : cubeNVData,  attrSize : 3, attrLoc : progDraw.inNV },
    { data : cubeColData, attrSize : 3, attrLoc : progDraw.inCol } ],
    cubeInxData );

    bufQuad.pos = gl.createBuffer();
    gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos );
    gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( [ -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0 ] ), gl.STATIC_DRAW );
    bufQuad.inx = gl.createBuffer();
    gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx );
    gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( [ 0, 1, 2, 0, 2, 3 ] ), gl.STATIC_DRAW );  
    
    camera = new Camera( [0, 3, 0.0], [0, 0, 0], [0, 0, 1], 90, vp_size, 0.5, 100 );

    window.onresize = resize;
    resize();
    requestAnimationFrame(render);
}

function resize() {
    //vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight];
    vp_size = [window.innerWidth, window.innerHeight];
    //vp_size = [256, 256]
    canvas.width = vp_size[0];
    canvas.height = vp_size[1];

    var fbsize = Math.max(vp_size[0], vp_size[1]);
    fbsize = 1 << 31 - Math.clz32(fbsize); // nearest power of 2

    blurFB = [];
    for ( var i = 0; i < 2; ++ i ) {
        fb = gl.createFramebuffer();
        fb.width = fbsize;
        fb.height = fbsize;
        gl.bindFramebuffer( gl.FRAMEBUFFER, fb );
        fb.color0_texture = gl.createTexture();
        gl.bindTexture( gl.TEXTURE_2D, fb.color0_texture );
        gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST );
        gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST );
        gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, fb.width, fb.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null );
        fb.renderbuffer = gl.createRenderbuffer();
        gl.bindRenderbuffer( gl.RENDERBUFFER, fb.renderbuffer );
        gl.renderbufferStorage( gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, fb.width, fb.height );
        gl.framebufferTexture2D( gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, fb.color0_texture, 0 );
        gl.framebufferRenderbuffer( gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, fb.renderbuffer );
        gl.bindTexture( gl.TEXTURE_2D, null );
        gl.bindRenderbuffer( gl.RENDERBUFFER, null );
        gl.bindFramebuffer( gl.FRAMEBUFFER, null );
        blurFB.push( fb );
    }
}

function Fract( val ) { 
    return val - Math.trunc( val );
}
function CalcAng( deltaTime, intervall ) {
    return Fract( deltaTime / (1000*intervall) ) * 2.0 * Math.PI;
}
function CalcMove( deltaTime, intervall, range ) {
    var pos = self.Fract( deltaTime / (1000*intervall) ) * 2.0
    var pos = pos < 1.0 ? pos : (2.0-pos)
    return range[0] + (range[1] - range[0]) * pos;
}    
function EllipticalPosition( a, b, angRag ) {
    var a_b = a * a - b * b
    var ea = (a_b <= 0) ? 0 : Math.sqrt( a_b );
    var eb = (a_b >= 0) ? 0 : Math.sqrt( -a_b );
    return [ a * Math.sin( angRag ) - ea, b * Math.cos( angRag ) - eb, 0 ];
}

function IdentM44() {
    return [ 1, 0, 0, 0,    0, 1, 0, 0,    0, 0, 1, 0,    0, 0, 0, 1 ];
};

function RotateAxis(matA, angRad, axis) {
    var aMap = [ [1, 2], [2, 0], [0, 1] ];
    var a0 = aMap[axis][0], a1 = aMap[axis][1]; 
    var sinAng = Math.sin(angRad), cosAng = Math.cos(angRad);
    var matB = matA.slice(0);
    for ( var i = 0; i < 3; ++ i ) {
        matB[a0*4+i] = matA[a0*4+i] * cosAng + matA[a1*4+i] * sinAng;
        matB[a1*4+i] = matA[a0*4+i] * -sinAng + matA[a1*4+i] * cosAng;
    }
    return matB;
}

function Rotate(matA, angRad, axis) {
    var s = Math.sin(angRad), c = Math.cos(angRad);
    var x = axis[0], y = axis[1], z = axis[2]; 
    matB = [
        x*x*(1-c)+c,   x*y*(1-c)-z*s, x*z*(1-c)+y*s, 0,
        y*x*(1-c)+z*s, y*y*(1-c)+c,   y*z*(1-c)-x*s, 0,
        z*x*(1-c)-y*s, z*y*(1-c)+x*s, z*z*(1-c)+c,   0,
        0,             0,             0,             1 ];
    return Multiply(matA, matB);
}    

function Multiply(matA, matB) {
    matC = IdentM44();
    for (var i0=0; i0<4; ++i0 )
        for (var i1=0; i1<4; ++i1 )
            matC[i0*4+i1] = matB[i0*4+0] * matA[0*4+i1] + matB[i0*4+1] * matA[1*4+i1] + matB[i0*4+2] * matA[2*4+i1] + matB[i0*4+3] * matA[3*4+i1]  
    return matC;
}

function Cross( a, b ) { return [ a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0 ]; }
function Dot( a, b ) { return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]; }
function Normalize( v ) {
    var len = Math.sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] );
    return [ v[0] / len, v[1] / len, v[2] / len ];
}

Camera = function( pos, target, up, fov_y, vp, near, far ) {
this.Time = function() { return Date.now(); }
this.pos = pos;
this.target = target;
this.up = up;
this.fov_y = fov_y;
this.vp = vp;
this.near = near;
this.far = far;
this.orbit_mat = this.current_orbit_mat = this.model_mat = this.current_model_mat = IdentM44();
this.mouse_drag = this.auto_spin = false;
this.auto_rotate = true;
this.mouse_start = [0, 0];
this.mouse_drag_axis = [0, 0, 0];
this.mouse_drag_angle = 0;
this.mouse_drag_time = 0;
this.drag_start_T = this.rotate_start_T = this.Time();
this.Ortho = function() {
    var fn = this.far + this.near;
    var f_n = this.far - this.near;
    var w = this.vp[0];
    var h = this.vp[1];
    return [
        2/w, 0,   0,       0,
        0,   2/h, 0,       0,
        0,   0,   -2/f_n,  0,
        0,   0,   -fn/f_n, 1 ];
};  
this.Perspective = function() {
    var n = this.near;
    var f = this.far;
    var fn = f + n;
    var f_n = f - n;
    var r = this.vp[0] / this.vp[1];
    var t = 1 / Math.tan( Math.PI * this.fov_y / 360 );
    return [
        t/r, 0, 0,          0,
        0,   t, 0,          0,
        0,   0, -fn/f_n,   -1,
        0,   0, -2*f*n/f_n, 0 ];
}; 
this.LookAt = function() {
    var mz = Normalize( [ this.pos[0]-this.target[0], this.pos[1]-this.target[1], this.pos[2]-this.target[2] ] );
    var mx = Normalize( Cross( this.up, mz ) );
    var my = Normalize( Cross( mz, mx ) );
    var tx = Dot( mx, this.pos );
    var ty = Dot( my, this.pos );
    var tz = Dot( [-mz[0], -mz[1], -mz[2]], this.pos ); 
    return [mx[0], my[0], mz[0], 0, mx[1], my[1], mz[1], 0, mx[2], my[2], mz[2], 0, tx, ty, tz, 1]; 
};
this.Orbit = function() {
    return Multiply(this.LookAt(), this.OrbitMatrix());
}; 
this.OrbitMatrix = function() {
    return (this.mouse_drag || (this.auto_rotate && this.auto_spin)) ? Multiply(this.current_orbit_mat, this.orbit_mat) : this.orbit_mat;
};
this.AutoModelMatrix = function() {
    return this.auto_rotate ? Multiply(this.current_model_mat, this.model_mat) : this.model_mat;
};
this.Update = function(vp_size) {
    if (vp_size)
        this.vp = vp_size;
    var current_T = this.Time();
    this.current_model_mat = IdentM44()
    if (this.mouse_drag) {
        this.current_orbit_mat = Rotate(IdentM44(), this.mouse_drag_angle, this.mouse_drag_axis);
    } else if (this.auto_rotate) {
        if (this.auto_spin ) {
            if (this.mouse_drag_time > 0 ) {
                var angle = this.mouse_drag_angle * (current_T - this.rotate_start_T) / this.mouse_drag_time;
                this.current_orbit_mat = Rotate(IdentM44(), angle, this.mouse_drag_axis);
            }
        } else {
            var auto_angle_x = Fract( (current_T - this.rotate_start_T) / 13000.0 ) * 2.0 * Math.PI;
            var auto_angle_y = Fract( (current_T - this.rotate_start_T) / 17000.0 ) * 2.0 * Math.PI;
            this.current_model_mat = RotateAxis( this.current_model_mat, auto_angle_x, 0 );
            this.current_model_mat = RotateAxis( this.current_model_mat, auto_angle_y, 1 );
        }
    }
};
this.ChangeMotionMode = function(drag, spin, auto ) {
    var new_drag = drag;
    var new_auto = new_drag ? false : auto;
    var new_spin = new_auto ? spin : false;
    change = this.mouse_drag != new_drag || this.auto_rotate != new_auto || this.auto_spin != new_spin; 
    if (!change)
        return;
    if (new_drag && !this.mouse_drag) {
        this.drag_start_T = this.Time();
        this.mouse_drag_angle = 0.0;
        this.mouse_drag_time = 0;
    }
    if (new_auto && !this.auto_rotate)
        this.rotate_start_T = this.Time();
    this.mouse_drag = new_drag; 
    this.auto_rotate = new_auto;  
    this.auto_spin = new_spin;
    this.orbit_mat = Multiply(this.current_orbit_mat, this.orbit_mat);
    this.current_orbit_mat = IdentM44();
    this.model_mat = Multiply(this.current_model_mat, this.model_mat);
    this.current_model_mat = IdentM44();
};
this.OnMouseDown = function( event ) {
    var rect = gl.canvas.getBoundingClientRect();
    if ( event.clientX < rect.left || event.clientX > rect.right ) return;
    if ( event.clientY < rect.top || event.clientY > rect.bottom ) return;
    if (event.button == 0) { // left button
        this.mouse_start = [event.clientX, event.clientY]; 
        this.ChangeMotionMode( true, false, false );
    }
};
this.OnMouseUp = function( event ) {
    if (event.button == 0) { // left button
        this.ChangeMotionMode( false, true, true );
    } else if (event.button == 1) {// middle button
        this.ChangeMotionMode( false, false, !this.auto_rotate );
    }
};
this.OnMouseMove = function( event ) {
    var dx = (event.clientX-this.mouse_start[0]) / this.vp[0];
    var dy = (event.clientY-this.mouse_start[1]) / this.vp[1];
    var len = Math.sqrt(dx*dx + dy*dy);
    if (this.mouse_drag && len > 0) {
        this.mouse_drag_angle = Math.PI*len;
        this.mouse_drag_axis = [dy/len, 0, -dx/len];
        this.mouse_drag_time = this.Time() - this.drag_start_T;
    }
};

this.domElement = document;
var cam = this;
//this.domElement.addEventListener( 'contextmenu', function(e) { event.preventDefault(); }, false );
this.domElement.addEventListener( 'mousedown', function(e) { cam.OnMouseDown(e) }, false );
this.domElement.addEventListener( 'mouseup', function(e) { cam.OnMouseUp(e) }, false );
this.domElement.addEventListener( 'mousemove', function(e) { cam.OnMouseMove(e) }, false );
//this.domElement.addEventListener( 'mousewheel', hid_events.onMouseWheel, false );
//this.domElement.addEventListener( 'DOMMouseScroll', hid_events.onMouseWheel, false ); // firefox
}

var ShProg = {
Create: function (shaderList) {
    var shaderObjs = [];
    for (var i_sh = 0; i_sh < shaderList.length; ++i_sh) {
        var shderObj = this.Compile(shaderList[i_sh].source, shaderList[i_sh].stage);
        if (shderObj) shaderObjs.push(shderObj);
    }
    var prog = {}
    prog.progObj = this.Link(shaderObjs)
    if (prog.progObj) {
        prog.attrInx = {};
        var noOfAttributes = gl.getProgramParameter(prog.progObj, gl.ACTIVE_ATTRIBUTES);
        for (var i_n = 0; i_n < noOfAttributes; ++i_n) {
            var name = gl.getActiveAttrib(prog.progObj, i_n).name;
            prog.attrInx[name] = gl.getAttribLocation(prog.progObj, name);
        }
        prog.uniLoc = {};
        var noOfUniforms = gl.getProgramParameter(prog.progObj, gl.ACTIVE_UNIFORMS);
        for (var i_n = 0; i_n < noOfUniforms; ++i_n) {
            var name = gl.getActiveUniform(prog.progObj, i_n).name;
            prog.uniLoc[name] = gl.getUniformLocation(prog.progObj, name);
        }
    }
    return prog;
},
AttrI: function (prog, name) { return prog.attrInx[name]; },
UniformL: function (prog, name) { return prog.uniLoc[name]; },
Use: function (prog) { gl.useProgram(prog.progObj); },
SetI1: function (prog, name, val) { if (prog.uniLoc[name]) gl.uniform1i(prog.uniLoc[name], val); },
SetF1: function (prog, name, val) { if (prog.uniLoc[name]) gl.uniform1f(prog.uniLoc[name], val); },
SetF2: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform2fv(prog.uniLoc[name], arr); },
SetF3: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform3fv(prog.uniLoc[name], arr); },
SetF4: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform4fv(prog.uniLoc[name], arr); },
SetM33: function (prog, name, mat) { if (prog.uniLoc[name]) gl.uniformMatrix3fv(prog.uniLoc[name], false, mat); },
SetM44: function (prog, name, mat) { if (prog.uniLoc[name]) gl.uniformMatrix4fv(prog.uniLoc[name], false, mat); },
Compile: function (source, shaderStage) {
    var shaderScript = document.getElementById(source);
    if (shaderScript)
        source = shaderScript.text;
    var shaderObj = gl.createShader(shaderStage);
    gl.shaderSource(shaderObj, source);
    gl.compileShader(shaderObj);
    var status = gl.getShaderParameter(shaderObj, gl.COMPILE_STATUS);
    if (!status) alert(gl.getShaderInfoLog(shaderObj));
    return status ? shaderObj : null;
},
Link: function (shaderObjs) {
    var prog = gl.createProgram();
    for (var i_sh = 0; i_sh < shaderObjs.length; ++i_sh)
        gl.attachShader(prog, shaderObjs[i_sh]);
    gl.linkProgram(prog);
    status = gl.getProgramParameter(prog, gl.LINK_STATUS);
    if ( !status ) alert(gl.getProgramInfoLog(prog));
    return status ? prog : null;
} };

var VertexBuffer = {
Create: function(attribs, indices, type) {
    var buffer = { buf: [], attr: [], inx: gl.createBuffer(), inxLen: indices.length, primitive_type: type ? type : gl.TRIANGLES };
    for (var i=0; i<attribs.length; ++i) {
        buffer.buf.push(gl.createBuffer());
        buffer.attr.push({ size : attribs[i].attrSize, loc : attribs[i].attrLoc, no_of: attribs[i].data.length/attribs[i].attrSize });
        gl.bindBuffer(gl.ARRAY_BUFFER, buffer.buf[i]);
        gl.bufferData(gl.ARRAY_BUFFER, new Float32Array( attribs[i].data ), gl.STATIC_DRAW);
    }
    gl.bindBuffer(gl.ARRAY_BUFFER, null);
    if ( buffer.inxLen > 0 ) {
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, buffer.inx);
        gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( indices ), gl.STATIC_DRAW);
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null);
    }
    return buffer;
},
Draw: function(bufObj) {
    for (var i=0; i<bufObj.buf.length; ++i) {
        gl.bindBuffer(gl.ARRAY_BUFFER, bufObj.buf[i]);
        gl.vertexAttribPointer(bufObj.attr[i].loc, bufObj.attr[i].size, gl.FLOAT, false, 0, 0);
        gl.enableVertexAttribArray( bufObj.attr[i].loc);
    }
    if ( bufObj.inxLen > 0 ) {
        gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, bufObj.inx);
        gl.drawElements(bufObj.primitive_type, bufObj.inxLen, gl.UNSIGNED_SHORT, 0);
        gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, null );
    }
    else
        gl.drawArrays(bufObj.primitive_type, 0, bufObj.attr[0].no_of );
    for (var i=0; i<bufObj.buf.length; ++i)
        gl.disableVertexAttribArray(bufObj.attr[i].loc);
    gl.bindBuffer( gl.ARRAY_BUFFER, null );
} };

initScene();

})();
</script>

</body>